Air heater



2 Sheets-Sheet l c. c. lsAAcsoN AIR HIEATER grwwvm CHAeL ES C. [SA AcsoNFiled Aug. 15, 1939 June 9, 1942.

June 9, 1942. c. c. lsAAcsoN AIR HEATER Filed Aug. 15, "1959 I 2Sheets-Sheet 2 CHAQL as C. [SAACSON Patented June 9, 1942 UNITED STATESPATENT OFFICE AIR HEATER Charles C. Isaacson, El Campo, Tex.

Application August 15, 1939, Serial N 0. 290,213

1 Claim.

This invention relates to an air heater.

An object of the invention is to provide an air heater of the characterdescribed specially designed for use in drying cotton which is tenderedto the cotton gin before it is sufiiciently dry to be efiicientlyginned. The heater, however, is adaptable for general use in heating airwherever it may be desired.

Another object of the invention is to provide a heater of the characterdescribed whereby the amount and temperature of the air may be easilyvaried so as to adapt the heater to the requirements to be met dependingon the state of the cotton to be dried.

It is a further object of the invention to provide an air heater whichis of a unitary structure all mounted on skids for easy handling andmounting. 7

It is a further object of the invention to pro-- vide an air heatingunit which is so designed as to conduce to the complete combustion ofthe fuel within the furnace chamber thus conducing to economy in fuelconsumption eliminating fire hazards and fumes and as a resulteliminating 2 closed within an outer shell spaced from the fur- 9 naceproper thus causing the outside or supplemental air to circulate throughthe space between the shell and the furnace walls to preheat said air aswell as to keep the walls cool thus in effect insulating the furnace,provision being made for mixing the supplemental air and the hot airfrom the furnace only after combustion has been completed in thefurnace, the supplemental air and the hot air from the furnace beingmixed and mingled in a mixing chamber provided for the purpose.

It is a still further object of the invention to provide an air heaterof the character described wherein the burners are mountedtangcntial tothe furnace walls so that the flame follows a spiralled course aroundthe furnace walls toward the mixing chamber. The course of the flamevaries depending on the velocity of the air current. Upon increase ofthe current velocity the centrifugal force will be correspondinglyincreased thus increasing the period of combustion automatically andconducing to a more efiicient combustion of the fuel.

With the above and other objects in View the invention has particularrelation to certain novel features of construction, operation andarrangethrough the mixing chamber.

ment of parts, an example of which is given in this specification andillustrated in the accompanying drawings, wherein:

Figure 1 shows a side elevation of the heater, partly in section.

Figure 2 shows a rear elevation.

Figure 3 shows a cross-sectional view taken on the line 3-3 of Figure 1.

Figure 4 shows a cross-sectional view taken through the mixing chamber.

Figure 5 shows a cross-sectional view taken on the line 55 of Figure 1.

Figure 6 shows a side view as viewed from the side opposite that shownin Figure 1.

Figure 7 shows a cross-sectional view taken on the line ll of Figure 1,and

Figure 8 shows an enlarged, fragmentary, sectional view taken on theline 88 of Figure 6.

Referring to Figure 1 the numerals 25 designate the spaced skids whereonthere is mounted a suction fan, or blower, 21, which discharges its airdirectly into the pipe 22. The fan impeller is mounted on and driven bya suitable shaft 28 rotatable in the bearings 29 and driven in anysuitable manner as through the pulley 30.

A tubular housing 3! enters one side of the fan casing and encloses amixing chamber 32 wherein the hot air from the furnace and thesupplemental air are thoroughly mixed. There is an outer jacket 33 whoseouter end is preferably cylindrical and whose inner end converges towardand merges into the outer end of the housing 3| as shown in Figure 1thus forming a Venturi passageway for the hot air as it enters andpasses Within the outer jacket 33 and spaced therefrom there is afurnace 3 3 which is shaped to conform to the shape of the outer jacket,its outer end being approximately cylindrical and its inner endconverging toward the mixing chamber and having an opening 35 into saidmixing chamber. This furnace is lined with suitable radiant material andits outer end is closed and provided with a sight opening 36 which maybe closed by a door 31 formed with transparent material. The outer endof the jacket is formed with arcuate screens 38 opposite the spacebetween the jacket and furnace for the inlet of supplemental air whichpasses inwardly through the said space around the furnace designated bythe numeral 39 in Figures 1 and 5. The jacket, furnace and fan 21 form aunitary structure on the skids.

The furnace is equipped with the inside burners as 40, 40. These burnersare so arranged that the flame will be emitted in an approximatelytangential direction with respect to the inside wall of the furnace asshown in Figure '7 so that the flame will travel, not only forwardly butalso in a spiralled direction about the furnace walls. The burners aresupplied with gas through the main gas pipe 4| which is equipped with amain control valve 42 and which branches into the branch pipes 43, 43,one going to each of the burners. Any type of burners may be employedbut it is preferable to use that type of burner shown and which is moreaccurately described in United States Patent No. 2,136,449, issued onthe 15th day of November, 1938. Each burner has the air inlet passageway44 for the inlet of air to support combustion. These air inlets 44 maybe opened, partially opened, or closed by the shutters 45 which aremounted on the transverse shafts 45 and which are connected by the links41 to move in unison. One of the shafts 46 is extended and mounted onsaid extended end there is a crank arm 48. A control lever 49 ispivotally connected at an intermediate point to the valve stem 50 of thecontrol valve 42. One end of this lever 49 is connected, by the link tothe free end of the arm 48 and its other end carries a weight 52normally tending to open the valve 42. The lever 49 is pivoted to afixed support at the point 49a, between the stem 50 and the weight 52.

Accordingly, as the valve 42 moves toward closed position to reduce thesupply of fuel to the burners, the shutters 45 will be correspondinglyclosed to reduce the supply of air to the furnace and as the valve 42 ismoved toward open position, the shutters 45 will be correspondinglyopened to increase the supply of air to the burners. The air and fuelwithin the furnace will therefore be retained at the required ratio toinsure efiicient combustion. Supplemental air will pass in directlythrough the screens 38 and will be heated by the furnace and will at thesame time form an insulation for the furnace walls to prevent suddenvariations in the temperature thereof. This supplemental air will moveon into the mixing chamber 32 moving past the baffles 53 which arespaced apart and are arranged across the space 39 adjacent the mixingchamber. They are spiralled in such a direction that the supplementalair will move in the direction indicated by the arrows in Figure 5 whichis the reverse of the direction of the hot air emerging from thefurnace, to the end that the currents of air will be moving in oppositedirections conducing to a thorough mixing of the two in the mixingchamber. The temperature of the air emerging from the furnace will thusbe reduced in the mixing chamber and will always be of a temperaturebelow the ignition point of the lint cotton to the end that there willbe no danger of igniting the lint; and the gas is substantially consumedin the furnace, so that the lint will not be liable to become ignitedand will not be discolored byhigh temperature or by unconsumed gas.

The main gas pipe 4| is equipped With a shut 01f valve 54 located outbeyond the control valve 42 whereby the supply of gas may be completelyout off and connected into the main gas pipe 4| out beyond the shut offvalve 54 there is a pilot gas line 55 which is controlled by anelectrically operable control valve 56- and which branches andterminates in nozzles as 51 through which a sufiicient supply of gas issupplied to sustain the pilot flames 58. Suitably anchored to thefurnace walls and extended into the furelectromagnetic valve 61.

nace there is a spark electrode 59, and the flame control electrode 6|]as shown in Figure 8.

The amount of gas going to the furnace is varied according to thetemperature of the furnace by controlling the valve 42 in a conventionalmanner as shown in Figures 6 and 8 and as hereinafter described. Mountedabove the valve 42 is a control unit which includes a diaphragm 6| whichis connected to the valve stem 50 and exposed to the atmosphere on thelower side thereof. Leading from the main gas line 4|, out beyond thevalve 54 and connected into the diaphragm housing is a branch gas line62 having a pressure regulating valve 63 therein and connected into thediaphragm housing so that gas pressure is exerted on the upper face ofthe diaphragm 6|. The gas pressure therefore forces the diaphragm 6| andstem 50 downwardly to close the valve 42. This downward movement of thevalve stem 50 is resisted by the weight 52 on the arm 48 which'weighttends to maintain the valve in open position. In order to allow thevalve 42 to open, gas pressure above the diaphragm must be relievedthrough a bypass connection 64 which is automatically controlled ashereinafter described. Also controlling the bypass line is a manuallyoperable valve 65. The end of the bypass line 64 terminates in thehousing of the spark electrode 59, and gas is allowed to pass throughthe bypass connection and housing into the furnace. The automaticcontrols for the bypass line comprise a thermostatic valve 66 which isadapted to be manually adjusted for various temperatures; and thecontrol further comprises an The construction of the thermostat valve isnot shown, but is of conventional construction, comprising a bellowshaving a valve connected thereto, the seat with which the valvecooperates being movable by the manual control 66a to thereby vary therelative position of the valve to the valve seat. The valve 42controlling the burners is yieldably maintained in open position by theweight 52 acting on the lever and link hereinbefore described. In orderto turn on the main burners, gas must be released from above thediaphragm 6! through the thermostatic valve 66 and electromagnetic valve61 discharging into the furnace around the electric spark electrode, thegas being then burned in the furnace. It can be seen that the positionof the valve 42 is changed by varying the pressure above the diaphragm6| by means of the thermostatic valve 66, therefore, the main valve isalso turned off if the temperature in the furnace rises too high, bythis thermostatic valve. In order to shut down the furnace theelectromagnetic valve 6! is closed, thereby building up pressure abovethe diaphragm and shutting off the valve 42. There will be no gasflowing into the furnace through the bypass connection 64 when thefurnace is shut down as the electromagnetic valve 61 is also closed.

It is contemplated that the furnace operation will be completelyautomatic, the electrical circuit and control being of conventionalconstruction, which construction is shown in Figures 6 and 8.

The heater, as hereinabove indicated, has been particularly designed foruse in drying cotto-n preparatory to ginning the same. However it is tobe noted that cotton to be ginned requires a certain amount of moisture.If the cotton is too dry, when ginned, the grade of cotton will belowered during the ginning process. Ordinarily the moisture content oflint cotton must exceed twelve (12%) per cent by weight in order tonecessitate the subjecting of the cotton to the drying process. If themoisture content of the cotton is substantially below said twelve percent, it is desirable, in order not to injure the cotton in ginning toincrease the moisture content. For that purpose a water pipe 84, leadingfrom a suitable source and controllable by a suitable valve, leads intothe discharge end of the fan housing 21, as shown in Figure 1. It mayterminate in a spray nozzle within said housing if desired. The watermay be sprayed into the hot air carrying the lint cotton in sufficientquantity to impart the desired moisture to the cotton. The water will beimmediately vaporized so that the moisture will reach the cotton in theform of a pipe 22 asindicated in Figure 10. This discharge end isequipped with conventional shutters 86, as shown in Figure 3, which maybe manually operated, or set, by means of an external crank 81 so as tocontrol the discharge of the heated air.

The drawings and description are illustrative merely, while the broadprinciple of the invention will be defined by the appended claim.

What I claim is:

A heater comprising a fan casing, a tubular housing entering one side ofthe fan casing and enclosing a mixing chamber, an outer jacket whoseouter end is cylindrical and whose inner end converges toward and mergesinto the outer end of the housing forming a Venturi passageway, afurnace lined with radiant material and located within, and spaced from,the jacket and shaped to conform to the shape of the jacket with itsouter end approximately cylindrical and closed and its inner endconverging toward but spaced from the mixing chamber and having an innerend opening directed toward the mixing chamber, the outer jacket havingits outer end substantially open around the furnace, said jacket.furnace, housing and easing forming a unitary structure, a burnerarranged in the outer end of the furnace to emit a flame substantiallytangent to the inside wall of the furnace, means in the fan casing forcreating an air current through said passageway around the furnace andthrough the mixing chamber to protect the walls of the furnace againstsudden variations in temperature, said air current creating a suction inthe furnace whereby the air passing inwardly through the passageway willbe caused to follow a spiral course about the furnace and the flame willbe caused to follow a spiral course around the furnace walls toward thefurnace outlet, the passageway about the furnace, and the furnace outletmerging adjacent the outer end of the housing to cause a mixture of theair with the fuel and a reduction of the temperature below the ignitionpoint.

CHARLES C. ISAACSON.

